Title : Polymeric metal Schiff base complexes as catalysts for photoelectrocatalytic hydrogen peroxide production
Abstract:
Hydrogen peroxide represents clean and convenient energy source for fuel cells. H2O2 is mostly produced in industry by anthraquinone process, where 2-alkylanthraquinone is reduced by Pd-catalyzed hydrogenation to 2-alkylanthrahydroquinone, which undergoes autoxidation in the presence of oxygen giving eventually hydrogen peroxide and resuming 2-alkylanthraquinone. Photocatalytic production of hydrogen peroxide by photo induced reduction of molecular oxygen represents an appealing alternative to anthraquinone process, as it might decrease the energy consumption and reduce the production cost. In this work, we report our study on possible application of metal Schiff base complexes as cheap photoredox catalysts for H2O2 production. Activity of [MII(L)]n complexes, where M is Ni, Cu or Pd and L is a tetradentate N,N,O,O ligand of Schiff base family, in the photoelectrocatalytic reduction of molecular oxygen to hydrogen peroxide has been demonstrated. The effect of pH of the medium and the ligand in the coordination sphere on the reaction rate and the photocurrent produced were studied, the maximal photocurrent and H2O2 concentrations achieved comprising 23 μA/cm2 and 1.2 mM respectively. The efficiency of H2O2 production reaches 97% after 6 hours of operation. Taking into account that complex is obtained from cheap commercial chemicals by using simple experimental techniques, the observed performance makes this material perspective for practical applications.
